If it's so easy I would like to invite you compile a list of every person in that Electoral College with a blip saying how they got there & how long they've been serving from each and every state. I've tried many times and got lost in all the gauze but if you've cracked the code then, by all means, please share because I couldn't do it. I am not at all being sarcastic either, rather I am humbled by the sophistication of it all. I really want that list because I think those people should be held under a microscope since many are free to make their selections at will, but it's hard to get someone under a microscope if you don't know who they all are.
If its easy it shouldn't be hard right?
It isn't hard, time-consuming, yes, but not really difficult. The ENTIRE list of electors, in some cases including their home addresses, is available on the NARA website, here:
http://www.archives.gov/federal-register/electoral-college/2008/certificates-of-ascertainment.html
The governor of each state (plus the Mayor for DC) must file a Certificate of Ascertainment with NARA before the College meets. NARA posts the certificates on their website these days. In addition, almost all of the states post a separate list along with information about the selection process in that state. Those links are here:
http://www.archives.gov/federal-register/electoral-college/state_links.html
Once you know the Elector's name, state, and party affiliation, it is a simple matter to ask that party's state chairman's office for the electors' CVs. I doubt that there are any that would turn you down, especially if you live in the state. Would it take some effort? Yes, but if you really want to know, 200 or so form emails shouldn't be too great a commitment.
As to electors changing their vote, that is almost as rare as hen's teeth. Electors who change their vote (which can only have any real effect in two states in any case: Nebraska and Maine, which allow proportional voting) are known as "faithless Electors" and there have only been 16 of them in the last 100 years. Being chosen as an elector is a political plum; those who are chosen tend to be VERY loyal party officials or elected state legislators who are put up for it by the party machinery in their states. Most of the time when an Elector changes a vote, it is because the candidate that he or she was pledged to has died, but occasionally it is done to make a political statement. If you do that, it is almost always a career-ender, and you go down in history for it. Not many people have the stomach to sacrifice power and end a career that way. (Ironically for this discussion, the last person to do it was an Elector from DC in 2000, who abstained from the vote in order to draw attention to DC's lack of a Congressional vote.)
With 48 states going winner-take-all, faithless Electors have no real power these days. In recent decades electors have only done it as a symbolic gesture when it was clear that their vote was not going to be any kind of tie-breaker.
EDITED to say: It occurred to me overnight that this response might be construed as veering too far into a discussion of politics. I didn't intend it that way, more as straight civics, but Mods, if you think it strays too far into dangerous territory, please go ahead and delete it.